As in the Oklahoma City case, the government would appear to have overwhelming evidence, which links Mr. Kaczynski to a series of bombings that killed three and injured 23. But, again similar to the McVeigh case, defense attorneys are vigorously challenging the validity of that evidence, seeking to block vital parts of it from Kaczynski's trial.

One dissimilarity, however, is that the government has not said if it will seek the death penalty against Kaczynski, as it has against McVeigh. This has prompted speculation that the the defendant will reach a plea bargain with the government.

Between now and November, when the trial is scheduled to begin in Sacramento, Calif., the defense will try to persuade a federal judge to disallow everything seized at Kaczynski's isolated Montana cabin as evidence.

"The key to this case is the material they obtained during the search," says attorney Malcolm Segal, a former assistant US Attorney who has followed the case. "If the search is illegal, then the 'taint' doctrine applies, and anything derived from the search would be suppressed."

The evidence obtained during the search includes a bomb and bombmaking materials, a typewriter on which Kaczynski is alleged to have composed letters and manifestos sent to explain the bombings, and a journal that federal authorities claim includes detailed admissions to making each of the explosive devices.

In March, defense lawyers filed a motion asking that all the evidence seized in the nine-day search be barred from use in court. The government's original warrant was "rife with false and misleading statements and omitted significant evidence tending to show Theodore Kaczynski was not the Unabomber," the defense motion said.

Legal experts consider this a logical defense strategy, but one with a small likelihood of success. The defense must prove that the undisclosed information would have been sufficient to cause a judge to question the "probable cause" for issuing a warrant.

The defense has challenged the FBI affidavit underlying the search on a number of points, among them:

*The affidavit cited a DNA comparative analysis, based on tests of postage stamps used by the bomber and of Kaczynski. But the defense says the stamps did not have enough DNA for valid testing. It also said agents failed to disclose that the FBI's lab excluded Kaczynski as the source of DNA on two letters.

*Defense attorneys say the affidavit failed to disclose evidence that gives Kaczynski an alibi for one of the fatal bombings.

*The affidavit twisted statements by Kaczynski's brother and mother that appear to place him at a locale where three bombings took place, the defense says.

*The affidavit failed to disclose that Kaczynski did not fit the physical description of the Unabomber provided by the only eyewitness to the crimes.

Of these objections, the key point is the DNA evidence, says San Francisco defense attorney Douglas Horngrad, who has represented numerous political activists. But the secondary aim, says Mr. Horngrad, is to undercut the fact that the defendant's brother and mother are among the government's chief witnesses.

The thrust of the defense strategy is to argue that the government failed to fully investigate other suspects, contrary to claims made in the FBI affidavit. The defense has asked for all 2,417 files on suspects during the FBI's 17-year hunt for the elusive serial bomber, including material on 12 people who were considered "priority" suspects. On Tuesday, a federal magistrate ordered prosecutors to hand over some of the documents and said that he himself would examine others before deciding whether to give them to the defense.

Even if the defense fails to suppress the search evidence, experts believe it will have achieved the goal of providing grounds for appeals of the verdict.